Emulsion with coke additive in hydrocarbon phase and process for preparing same

ABSTRACT

A process for preparing a hydrocarbon in water emulsion includes the steps of providing a hydrocarbon phase containing inactive natural surfactant; mixing a solid carbon additive with the hydrocarbon phase, the solid additive being selected from the group consisting of coal, coke and mixtures thereof so as to provide a hydrocarbon suspension including the solid carbon additive; and forming an emulsion from the hydrocarbon suspension and an aqueous phase in the presence of a surfactant activating additive so as to activate the inactive natural surfactant and form a hydrocarbon in water emulsion having the solid carbon additive suspended in the hydrocarbon phase. A hydrocarbon in water emulsion is also provided including a hydrocarbon phase, a water phase, a surfactant, and a solid carbon additive suspended in the hydrocarbon phase, the solid carbon additive being selected from the group consisting of coal, coke and mixtures thereof.

This is a Division, of application Ser. No. 09/057,879, filed Apr. 9,1998, now U.S. Pat. No. 6,069,178.

BACKGROUND OF THE INVENTION

The invention relates to a hydrocarbon in water emulsion and process forpreparing same and, more particularly, to an emulsion and processincluding a solid carbon additive, especially coal or coke, which isuseful in enhancing the energy potential of the emulsion as a fuel, andwhich also allows the emulsion to be used in paving procedures, whilemaintaining stability of the emulsion during transportation and storage.

Refineries on a worldwide basis produce large amounts of coke, thedisposal of which can pose problems. This coke typically is present as asolid, further complicating the proper disposal of same.

The need exists for a technique or method which utilizes coke so asprovide an advantageous disposition of same.

Bitumen emulsions are typically used as a source of combustible fuel.One problem frequently encountered with such fuel is that the sulfurcontent of the bitumen poses problems.

The need also remains for a bitumen emulsion wherein a reduced sulfurcontent is provided per unit of energy produced.

It is therefore the primary object of the present invention to provide amethod for incorporating coke into an emulsion for use as a combustiblefuel and/or in paving procedures.

It is a further object of the present invention to provide a method forincorporating solid carbon additives such as coal or coke into a bitumenin water emulsion so as to provide a material useful as a combustiblefuel having a reduced sulfur content per unit of energy produced or as apaving material.

Other objects and advantages of the present invention will appearhereinbelow.

SUMMARY OF THE INVENTION

In accordance with the present invention, the foregoing objects andadvantages are readily attained.

According to the invention, a process for preparing a hydrocarbon inwater emulsion is provided, which process comprises the steps of:providing a hydrocarbon phase; mixing a solid carbon additive with saidhydrocarbon phase, said solid carbon additive being selected from thegroup consisting of coal, coke and mixtures thereof so as to provide ahydrocarbon suspension including said solid additive; and forming anemulsion from said hydrocarbon suspension and an aqueous phase in thepresence of a surfactant so as to form a hydrocarbon in water emulsionhaving said solid additive suspended in said hydrocarbon phase.

In further accordance with the present invention, a hydrocarbon in wateremulsion is provided which is extremely useful as a combustible fuel oras a paving material, which emulsion comprises a hydrocarbon phase, awater phase, a surfactant, and a solid carbon additive suspended in thehydrocarbon phase, said solid carbon additive being selected from thegroup consisting of coal, coke and mixtures thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention relates to a hydrocarbon in water emulsion and process forpreparing same, and particularly to a viscous hydrocarbon or bitumen inwater emulsion, wherein the bitumen is provided with a solid carbonadditive suspended therein which renders the emulsion useful as a pavingmaterial and also as a combustible fuel, and which further serves toprovide an emulsion having excellent stability at a reasonable cost.

The hydrocarbon phase of the emulsion and process of the presentinvention may suitably be any hydrocarbon, especially viscoushydrocarbon, from which it is desirable to form emulsions in water so asto enhance the transportability thereof. Emulsions of viscoushydrocarbon in water are useful as a combustible fuel and, according tothe invention, as paving materials for use in paving roads and the like.

Most naturally occurring viscous hydrocarbon material contains inactivesurfactants including carboxylic acids, phenols and esters which, underproper conditions, can be activated as surfactants.

These inactive natural surfactants can be activated and stabilized usingadditives. The use of amine additives to activate the inactive naturalsurfactants is disclosed in U.S. Pat. No. 5,480,583 to Rivas et al.

The incorporation of additional components into emulsions can veryfrequently have a destabilizing or other adverse effect on the resultingemulsion. In accordance with the present invention, however, it has beenfound that by using amine additives to activate the natural surfactantscontained in the heavy hydrocarbon phase, a stable emulsion includingthe solid carbon additive incorporated into the hydrocarbon phase can beprovided.

According to the invention, the solid carbon additive to be used maysuitably be a particulate coke additive, which provides an emulsionwhich is well suited for use in paving operations, or a particulate coaladditive which can be used to maintain the energy levels produced bycombustion of the emulsion, while potentially reducing the overallsulfur content of the emulsion as desired through the use of lowersulfur coal, which is particularly advantageous in light of desired orrequired emission levels of combustion processes.

The solid carbon additive, either coal or coke, may typically beobtained having a solid structure of widely diverse particle size. Inaccordance with the present invention, this solid is preferably treated,for example using milling and the like, to reduce the particle size ofthe solid carbon additive, preferably to a size less than or equal toabout 30 microns. This may be carried out, for example, using avibratory cryogenic mill such as the 6700 Freezer Mill of SPEXIndustries. Of course, if the starting material is obtained alreadyhaving the desired particle size, no additional milling is needed.

The hydrocarbon phase is preferably a viscous hydrocarbon having an APIgravity of less than or equal to about 16, preferably less than or equalto about 8.1, and a viscosity at 120° F. of greater than or equal toabout 100 cp. A specific example of a suitable hydrocarbon for use inaccordance with the present invention is Cerro Negro bitumen, which maytypically have the following composition.

TYPICAL CERRO NEGRO BITUMEN Gravity API 60° C. 8.1 Saturates % (wt.)29.4 Aromatics % 35.6 Resins % 18.9 Asphaltenes % 16.1 Acidity (mgKOH/g) 3.02 Carbon % 80.3 Hydrogen % 9.9 Nitrogen (ppm) 6188 Sulfur %3.7 Vanadium (ppm) 367.4 Nickel (ppm) 95.5 Sodium (ppm) 11.8 ConradsonCarbon % 17.2 Water % 0.1

The water or aqueous phase of the emulsion may suitably be water fromany convenient source, and preferably includes the amine additive foractivating the natural surfactant of the bitumen. Suitable amineadditives include combinations of amines and sodium hydroxide (NaOH) asdescribed in U.S. Pat. No. 5,480,583.

The aqueous phase of the emulsion is preferably provided containing theamine additive in an amount corresponding to between about 800 ppm andabout 2500 ppm wt. with respect to the bitumen.

In accordance with the present invention, it has also been found thatthe mixing of a solid carbon additive with the hydrocarbon phase,wherein the solid additive is mixed in a specific ratio to thehydrocarbon phase, and is present at desired particle sizes ordiameters, serves to enhance the stability of the emulsion while alsoenhancing the combustion and/or paving characteristics of the emulsion.Solid carbon additives in accordance with the present invention arepreferably oil insoluble, and may include coal, coke resulting frombituminous coal or petroleum processes and the like, and mixturesthereof.

In accordance with the present invention, the solid carbon additive ispreferably provided having an average particle size less than or equalto about the mean droplet size of the hydrocarbon phase in the finalemulsion such that the solid particles remain suspended withinhydrocarbon droplets as desired. In this regard, the solid carbonadditive of the present invention is preferably provided having anaverage particle size less than a mean volume diameter (D_((4,3))) ofthe hydrocarbon, wherein the mean volume diameter is defined as follows:

D _((4,3))=(Σdi ⁴ /vi)/(Σdi ³ /vi),

wherein di is the mean diameter of band “i” of a histogram of theemulsion, and vi is the accumulated volume of droplets in thatparticular band. The solid additive in accordance with the presentinvention is preferably provided having an average particle size of lessthan or equal to about 30 microns, most preferably less than or equal toabout 15 microns.

The solid additive is preferably also mixed with hydrocarbon inaccordance with the present invention in amounts which are less than orequal to about 10% wt. of the hydrocarbon, or 800 ppm based on totalemulsion, so as to further reduce the possibility for sedimentation ofthe solid additive. In this regard, it has been found that solidadditive may suitably be mixed with the hydrocarbon according to thefollowing relation

Φ_(S)/(Φ_(H)+Φ_(S))≦K,

wherein Φ_(S) is the volume fraction of the solid additive, Φ_(H) is thevolume fraction of the hydrocarbon, and K is 0.1.

In order to insure the internal dispersion of solid additive through thehydrocarbon or bitumen phase, the bitumen may preferably be heated to atemperature sufficient to allow substantially homogeneous mixture. Forexample, Cerro Negro bitumen may suitably be heated to a temperature ofat least about 60° C. or higher prior to mixing with the solid additive.

The emulsion of the present invention may preferably be prepared asfollows. Initially, the viscous hydrocarbon phase is provided. Thedesired solid additive in accordance with the present invention is alsoprovided, and may need to be milled or otherwise treated so as toprovide a suitable average particle size.

The solid particles are then mixed with the hydrocarbon phase,preferably heated as discussed above, so as to allow the internaldispersion of the solid within the hydrocarbon. This suspension of solidparticles in hydrocarbon is then used to form a hydrocarbon in wateremulsion by mixing with an aqueous phase as discussed above, andsubjecting the mixture to sufficient mixing energy so as to provide anoil-in-water emulsion preferably having an average droplet size of thehydrocarbon phase of between about 1 μm and about 30 μm, and having aratio by volume of hydrocarbon/water of between about 85/15 and about70/30. Most preferably, in accordance with the present invention, theemulsion may be formed by mixing the hydrocarbon/solid suspension with aportion of the aqueous phase so as to provide an 85/15 emulsion, andsubsequently diluting the emulsion to a desired 70/30 ratio.

The solid carbon particles, either coke or coal, are preferablydispersed in the bitumen in a blending process which may be carried outfor a time preferably between about 1 and about 10 minutes, morepreferably between about 2 and about 4 minutes and at a temperature ofbetween about 50° C. and about 90° C., more preferably between about 65°C. and about 75° C. The solid carbon particles and bitumen arepreferably blended at a ratio by weight of bitumen to particles ofbetween about 1:1 and 25:1.

Once the solid carbon additive has been provided having the desiredparticle size, and in the proper amounts based upon the bitumen, thefinal emulsion is formed using bitumen with suspended solid and a waterphase which may preferably be provided with the additive, for examplecontaining about 2000 mg/l of monoethanolamine and, preferably, having asodium concentration equivalent to about 20 mg/l of Na+ ions in thefinal emulsion. As set forth above, the monoethanolamine and NaOH serveto activate natural surfactant present in the bitumen and to provide afinal emulsion product having suitable stability.

During the mixing stage, the bitumen is preferably maintained at atemperature of about 60° C., and the water with amine/NaOH additive ismixed in a mixer preferably during a pre-mixing stage at 200 rpm forabout 2 minutes, followed by mixing at 1500 rpm for an additional 2minutes so as to provide a stable emulsion. At this stage, the bitumenwith solid and water are preferably mixed so as to provide an emulsionhaving a ratio by volume of bitumen to water of between about 80/20 andabout 90/10, preferably about 85/15. This intermediate emulsion is thendiluted using additional water, preferably to a final emulsion having abitumen/water ratio of about 70/30. The dilution may suitably be carriedout while mixing for a period of about 1 minute, preferably at about1000 rpm.

This invention may be embodied in other forms or carried out in otherways without departing from the spirit or essential characteristicsthereof. The present embodiment is therefore to be considered as in allrespects illustrative and not restrictive, the scope of the inventionbeing indicated by the appended claims, and all changes which comewithin the meaning and range of equivalency are intended to be embracedtherein.

What is claimed is:
 1. A hydrocarbon in water emulsion comprising ahydrocarbon phase wherein said hydrocarbon phase is a viscoushydrocarbon having an API gravity of less than or equal to about 16, anda viscosity at 122° F. of greater than or equal to about 100 cp; a waterphase; and a sole surfactant consisting of a natural surfactant derivedfrom said hydrocarbon phase containing the natural surfactant, saidnatural surfactant having carboxylic acids, phenols, esters and mixturesthereof in inactive form and a natural surfactant activating agentconsisting of an amine additive, optionally with NaOH; and a solidcarbon additive suspended in the hydrocarbon phase, said solid carbonadditive being selected from the group consisting of coal, coke andmixtures thereof and being present in a ratio by weight of hydrocarbonto solid carbon additive of between about 1:1 to 25.1.
 2. An emulsionaccording to claim 1, wherein said hydrocarbon is Cerro Negro bitumen.3. An emulsion according to claim 1, wherein said solid carbon additiveis coke.
 4. An emulsion according to claim 1, wherein said solid carbonadditive is coal.
 5. An emulsion according to claim 1, wherein saidsolid carbon additive has an average particle size of less than or equalto about a mean droplet size of said hydrocarbon phase in said emulsion.6. An emulsion according to claim 1, wherein said solid carbon additivehas an average particle size which is less than a mean volume diameterD_((4, 3)) of said hydrocarbon, which is defined as follows: D_((4, 3))=(Σdi ⁴ /vi)/(Σdi ³ /vi), wherein di is mean diameter of band Iof a histogram of said emulsion, and vi is accumulated volume ofdroplets in said band.
 7. An emulsion according to claim 1, wherein saidsolid carbon additive has an average particle size of less than or equalto about 30 μm.
 8. An emulsion according to claim 1, wherein said solidcarbon additive has an average particle size of less than or equal toabout 15 μm.
 9. An emulsion according to claim 1, wherein said solidcarbon additive is present in said emulsion in an amount less than orequal to about 10% wt. of said hydrocarbon.
 10. An emulsion according toclaim 1, wherein said solid carbon additive is present in said emulsionaccording to the following: Φ_(S)/(Φ_(H)+Φ_(S))≦K, wherein Φ_(S) isvolume fraction of said solid carbon additive, Φ_(H) is volume fractionof said hydrocarbon, and K is 0.1.
 11. An emulsion according to claim 1,wherein said hydrocarbon phase and said water phase are present at aratio by volume of hydrocarbon/water between about 70/30 and about85/15.
 12. An emulsion according to claim 1, wherein said hydrocarbonphase has an average droplet diameter of between about 1 μm and about 30μm.
 13. An emulsion according to claim 1, wherein said surfactantactivating agent consisting of an amine and sodium hydroxide in amountseffective for activating said natural surfactant to stabilize theemulsion.
 14. An emulsion according to claim 13, wherein said emulsioncontains said amine in an amount between about 800 ppm and about 2500ppm based on weight of said hydrocarbon phase.